The binding and printing industries often rely on high-speed sheet material handling systems for printing, collating, binding, and otherwise handling sheet material, for example, sheets of paper. This sheet material, for example, individual sheets, newspapers, magazines, inserts and “onserts” (that is, sheet material used when collating newspapers), free-standing inserts (FSIs), books, brochures, and the like, is typically, fed to and accumulated in containers or “magazines” or “hoppers” and withdrawn from the magazines or hoppers and forwarded to a collating conveyor. One particular sheet material that is handled in the binding and printing industry is what is known in the art as a “signature.” A signature typically comprises two or more sheets of paper that may be folded to form a spine, that is, a “spine fold.” Signatures may contain four or more pages of text or graphics, for example, 30 or more pages of text or graphics.
In the manufacture of books or the assemblage of newsprint, it is common to assemble the book on a collecting or collating conveyor by sequentially withdrawing signatures from magazines, or hoppers, containing stacks of signatures. In producing a book, typically, a plurality of serially arranged hoppers, separating devices, and feeders are employed for gathering and collating the printed sheets of, for example, signatures. Typically, the separating devices separate and withdraw the sheet material from the hoppers and feed the sheet material to a rotating drum. The rotating drum then feeds the sheet material to a conveyor that collects and transfers the separated printed sheets for collation, binding, or other handling. The separation of the sheet material from the stacked sheet material is typically effected by a rotating disk separator. One typical disk-type separator is disclosed in U.S. Pat. No. 6,193,229, the disclosure of which is incorporated by reference herein in its entirety. The disk separator separates and feeds the sheet material to a rotating drum that accepts and retains the sheet material and conveys it to the conveyor. The conveyor that receives the sheet material is typically a horizontal conveyor. This horizontal conveyor may also receive sheet material from other, typically serially positioned, feeding drums.
The hoppers from which the rotating drum conveyor withdraws signatures is typically fed by one or more conveyors, for example, one or more conveyors upon which signatures are mounted, for instance, manually or automatedly, which convey the signatures to the hoppers. The timing of feeding and transferring of signatures from conveyor to hopper, from hopper to feeder, and from feeder to collating conveyors is often critical to the proper operation of the feeder and the proper assembly of the signatures on the collating conveyor. Misfeeds and jamming may occur when the timing of feeding and conveying is not optimum, for example, signatures may back up on a conveyor that feeds too quickly or a hopper may be depleted when a conveyor is not operated fast enough.
Aspects of the present invention address the disadvantages of prior art signature feeding and conveying systems by relating the speed of conveyors to the speed of the collating conveyor whereby backups and jamming of signatures during convey are minimized or even eliminated.